Pentagon efforts to seek the death penalty for six Guantánamo detainees suspected of involvement in the 9/11 terror attacks will pose a substantial test for a makeshift military-tribunal system, which has yet to produce a single verdict at trial.

All six were charged with conspiracy to commit war crimes, including murder, attacking civilians and civilian property, terrorism, and providing material support to terrorists.

Under Defense Department procedures, the charges will now be forwarded to the convening authority for military commissions, Susan Crawford, a former military appeals court judge, who must determine if there is probable cause to support the charges and whether to approve the potential punishment of death.